Three-dimensional molecular model

ABSTRACT

A three-dimensional molecular model comprises plastic modules, each representing on atom connected to one another. Modules intended to represent atoms of cyclic compounds are polyhedrons set in the model so that adjacent polyhedrons touch faces and have a common apex. The sum total of the angles formed by the adjacent faces of polyhedrons of the modules is more than 360°.

FIELD OF THE INVENTION

This invention relates to scientific visual aids and is moreparticularly concerned with three-dimensional molecular models.

BACKGROUND OF THE INVENTION

Three-dimensional molecular models are modules made of plastic, forexample, and connected to one another. Such modules can be made ashemispheres, cut-off spheres or polyhedrons. Each module represents anatom. The radius of a hemisphere represents the Van der waals atomicradius, while the distance from the center of the sphere to the cut-offplane is the covalent atomic radius. Connecting members of modulesrepresent interatomic bonds while the angles between their geometricaxes are valency angles. Conformal displacement of atoms is representedby turning individual modules or whole sets about connecting members.

Known in the art is a three-dimensional molecular model comprisinghollow plastic modules made as hemispheres, cut-off spheres orpolyhedrons. Each module is provided with one or several openings to fitconical elements of connecting members (cf., for example, U.S. Pat. No.3,170,246 C1. 35-18, 1965).

Also known in the art is a three-dimensional molecular model comprisingplastic modules each representing one atom of a molecular structure.Modules are joined together by connecting members fitted into sockets ofthe modules. Plastic modules designed to represent atoms of cycliccompounds are made as regular polyhedrons whose faces are adjacent sothat the model has one common apex (cf., for example, advertisingbooklet of the Ealing Corporation, South Natick, Mass., CPK PrecisionMolecular Models, 1980, pp. 27 and 30).

The above known three-dimensional molecular models are deficient in thatthey can represent only planar cyclic compounds. This is conditioned bythe fact that, when models of cyclic compounds are put together, thecenters of modules are located in one plane, which can be conditionallyreferred to as the cycle plane, and the sum of the angles formed byadjoining faces of the polyhedrons is equal to or less than 360°, sothat a single atom or several atoms cannot be brought out of the cycleplane.

SUMMARY OF THE INVENTION

This invention is to provide a three-dimensional model of a molecularstructure, wherein modules are made so that it becomes possible torepresent aplanar cyclic compound structures.

There is provided a three-dimensional molecular model comprising plasticmodules, each module represents one atom of a molecular structure, whichare connected to one another, plastic modules which are intended torepresent atoms of cyclic compounds are made as polyhedrons and placedin the model so that adjoining polyhedrons touch their faces and have acommon apex, wherein, according to the invention, in order to provide anaplanar cyclic compound composed of at least three plastic modules, theplastic modules of this model are made so that the sum of the anglesformed by adjoining faces of the module polyhedrons are more than 360°.

It is advisable that the plastic module representing atoms of cycliccompounds should be made as an irregular polyhedron.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference tospecific embodiments thereof and accompanying drawings wherein:

FIG. 1 is a perspective view of a three-dimensional molecular model;

FIG. 2 is a sequential view of the molecular model of FIG. 1 showing twomodules turned in relation to their axes;

FIG. 3 illustrates a module of a molecular model;

FIG. 4 is a sequential view of the molecular model illustrated in FIG. 2having an aplanar cyclic atomic bond;

FIG. 5a is a schematic drawing of valency angles of deoxyribose andribose molecules;

FIG. 5b is a schematic drawing of planar angles about the center ofdeoxyribose and ribose molecules;

FIG. 6a is a schematic drawing of valency angles in a three-dimensionalmodel of deoxyribose and ribose molecules; and

FIG. 6b is a schematic drawing of angles about the center ofthree-dimensional deoxyribose and ribose molecules.

DETAILED DESCRIPTION OF THE INVENTION

A three-dimensional molecular model comprises interconnected plasticmodules 1 and 2 (FIGS. 1 and 2), each module representing one atom of amolecular structure. The modules 1 are approximately tetrahedrons whosefaces 3 and 4 are provided with sockets 5 for connecting the modules toone another during assembly of the model. Modules 2 are hemisphereshaving parts of their surfaces cut off to form faces for contact withadjoining modules 1.

Referring to FIGS. 1 and 2, a part of a model comprises five adjoiningmodules, four of which have an approximately equal apex angle α. Allmodules have a common apex 6. In order to put together a model of anaplanar cyclic compound composed of five modules having their centers indifferent planes, two modules 1 are turned about their axes where saidmodules are connected to adjacent modules in the direction of arrows Auntil the angle β between faces 7 and 8 is sufficient to fit in a fifthmodule 9 (FIG. 3) which, in turn, is an irregular polyhedron whose facesadjoin at angles not equal to the angle β. FIG. 4 shows athree-dimensional molecular model having an aplanar cyclic atomicstructure made as described above.

FIGS. 5 and 6 demonstrates an example of finding valency angles for adeoxyribose and ribose molecule. Structural roentgenography hasestablished that internal valency angles are equal to 101.3°, 102.4°,104.4°-106.1°, 109.2°-110.0°, 105.6°-107.3° and their total amounts to525°. The angles formed by the planes 10 around the molecule center areequal, respectively, to 78.7°, 77.6°, 75.6°-73.9°, 70.8°-70.0°,74.4°-72.7° and their total is 375°. The model of such a molecule hasvalency angles of 104° and 110° with a total of 526°, the sum of anglesat the molecular center being 374°, which is composed of angles of 76°and 70°.

The molecular model having an aplanar cyclic structure connection isformed as follows.

Four modules 1 and 2 are connected to one another, then two of these areturned about their axes of connection in one direction. The space 11(FIG. 2) thus formed is used to fit the fifth module 9 so that itbecomes somewhat prominent in relation to other modules.

Industrial Applicability

This invention can be used for scientific research and instructivepurposes to present a three-dimensional structure of molecules and theirtransformations. The invention is used for deciphering andinterpretation of initial data obtained by structural crystallography ofchemical substances and to find their most probable structural states.

I claim:
 1. A three-dimensional molecular model comprising at leastthree plastic modules having a polyhedral shape connected together tosimulate atoms of aplanar cyclic compounds having no more than fiveconstituent elements in each of said cyclic compounds and whereinadjacent plastic modules are arranged in said molecular model with facestouching, having a common apex, and having a sum of angles formed bysaid faces of said adjacent plastic modules equaling more than 360°. 2.A three-dimensional molecular model according to claim 1, wherein saidplastic modules representing said atoms of said cyclic compounds have anirregular polyhedral shape.